Fuel feeding mechanism



Dec. 17, 1935. J TURNER r AL I 2,024,839

FUEL FEEDING MECHANISM Filed April 5, 1933 3 Sheets-Sheet 1 Dec. 17, 1935.

J. F. TURNER El AL FUEL FEEDING MECHANISM Filed. April 5, 1933 3 Sheets-Sheet 2 I A TTORNEY .Dec. 17, 1935. J, F, TURNER HAL 2,024,839

FUEL FEEDING MECHANISM Filed April 5, 1933 3 Sheets-Sheet 3 Patented Dec. 17, 1935.

PATENT OFFICE 2,024,839 roan FEEDING MECHANISM James F. Turner and Christian P. Breidenbaugh, Baltimore, Md., assignors to Flynn & Emrlch Company, Baltimore, Md., a corporation of Maryland Application .April 5, 1933, Serial No. 664,498

1 Claim.

The object of the present invention is toprovide a fuel feed for underfeed stokers which is adapted to feed the fuel under all conditions from a hopper which is spaced away from the front of the furnace and fire door by-a suil'i- "cient distance to give free access 'to the fire door and which at the same time provides a uniform and dependable feed of the fuel to the ram and by the ram to the retort and hence to "the combustion area without difficulty as to cramping or clogging or any undesired cessation of the feed, the presentation of the coal or other fuel to the furnace bearing a uniform ratio to the reciprocation of the ram and being,

5 therefore, subject to whatever regulation is desired.

The apparatus of the invention is particularly adapted to relatively small power plants for the boiler rooms of schools, hospitals, institutions,

20 oflice buildings andthe like for which purpose.

it is designed, although it is capable of more general application. By its use it is possible to locate the fuel hopper at any necessary distance from the -boiler front without the danger of 25 having the coal pack and jam in the stoker; This device conveys just the right amount of coal easily and quickly to the front of the ram which is only required to push. the coal the same distance as though the hopper were im- 30 mediately next to the front of the boiler. There is therefore no danger of the coal packing and yet there is the full advantage of the ram feed which is regarded as superior to all others fo'r use in the underfeed type of stoker. Further- 5 more, as hereinafter described, the bottom of the hopper is always in motion so that the coal can not bridge in the hopper, an important advantage in favor of the new apparatus.

In the accompanying drawings we have illus- 40 trated a stoker of the ram type embodying the features of the invention in the preferred form,

making it possible to locate the fire door at the center of the front of thefurnace, with the retort, the ram and the hopper directly in line 45 with the fire door; the hopper being spaced backwardly from the'fire door so as to avoid any obstruction to the'fire door which will prevent free access thereto for the purpose of raking, breaking clinker, etc. by means of a hand 50 slicer bar.

connecting the bottom of the hopper to the ram passage and the retort.

Figure 2 is a' horizontal section through the furnace on a plane near the center of the-fire door, the hopper and connecting passages be- 5 ingshown in plan, the view being taken from the line 2, 2 in Figure 1 looking downward.

Figure 3 is a front elevation of the furnacethe ram and fuel feed passage being sectioned on the line 3, 3 in Figure 1, indicating a plane in transverse eto the plane of Figure 2.

Figure 4 is a vertical section on the line 4, I in Figure 1 taken transversely to the plane of Figure 1. I

Figure 5 is a. perspective view of the bottom feed ram, a portion of the same being broken away to show the rack teeth by which the preferred form of ram illustrated is operated.

Referring to the drawings by numerals, each of which is used, to indicate the same or similar parts in the different figures, the apparatus as shown comprisesa furnace I,- having'a fire door 2. This furnace is equipped with a stoker of the underfeed type including the grate 3 having a central retort 4 and dropbars or ash plates 5 at the side in accordance with the approved construction of this type of grate.

The apparatus also includes the fuel hopper 6 of any suitable typepreferably located in direct fore and aft alignment with the retort l.

The hopper 6 as shown is connected at the bottom by the fuel passage I with the forward por tion of the ram passage 8 in which the usual type or any suitable type of ram 9 is mounted to reciprocate preferably in direct alignment with the retort 4; This ram 9 is operated in any suitable manner as by means of a hydraulic motor indicated in a general way by reference character Ill, it being understood that the details of the motor are not material to the pres- 40 cut invention except that it must be regarded as essential that means be provided which will impart a suitable reciprocating motion to the ram in accordance with the approved practice. In addition to the ram proper, the illustration includes a coal pusher rodll extending well forward into the retort and having a secondary ram or coal pusher member l2 secured thereto in any suitable manner. l.

The illustration also includes a suitable control valve mechanism for the hydraulic motor illustrated at M, an electric or any other suitable motor or equivalent actuating means l5 and a pump l6 operated thereby to provide fluid under pressure to operate the hydraulic motor.

The electric motor 15 is connected to the pump IS in any suitable manner. The drivin connection from the motor to the pump in the form of the invention shown consists of a chain and sprocket connection enclosed in a casing II, it being understood that any suitable driving means may be employed.

An important feature of the invention resides in the improved movable hopper bottom, otherwise known as a hopper bottom feed ram or secondary ram I8 per se and in connection with the ram 9 and the passage I, leading from the hopper to the ram passage'B and retort throat l9, whereby it is .made possible to space the hopper back from the fire door to avoid obstruction to the same and provide for free operation of the slicer bars and other tools. By means of the improved device of the invention,.

it is made possible to space the hopper backwardly from the fire door to give freedom of access thereto without interference with the regularity and efiiciency of the fuel feed from the hopper to the ram passage 8 and the feed of the fuel by the ram to and through the retort 'to the combustion chamber.

The hopper bottom feed l8, in the form of the invention shown consists of a plate orblock of suitable height 'as three or four inches and of a width corresponding to the width of the hopper. This block is provided with means whereby it is reciprocated in a manner causing it to cooperate with the feeding action of the ram.

In the form of the invention shown, the block is provided with a toothed rack 2| downwardly disposed and having its operative length arranged in the direction of feed. The block l8 may to advantage be grooved upwardly or inwardly from the bottom surface to shield the teeth from grit and fuel particles, the raclcv teeth being located in the groove. Cooperating with the rack. 2| in the form of the invention shown is a toothed sector 22, pivotally mounted at 24 beneath the block 20 and provided with an operating arm 25 disposed oppositely to the toothed portion and shown as extending downwardly. This is formed at its lower end with a forked portion 26 which straddles the piston rod 21 of the hydraulic motor III which actuates the ram 9.

The piston rod 21, in turn, is provided with spaced abutments 28 and 29, the latter being adjustable. The abutments 29 and 29 engage the forked end 26 of the arm 25 on the forward and return strokes of the-ram, swinging the arm 25 through a predetermined stroke about the center 24, and imparting a corresponding reverse stroke to the hopper bottom feed it.

It will be noted that the passage 1 leads from the bottom of the hopper preferably at the side adjacent the furnace and that the opposite side of the hopper at the bottom is in the preferred form inclined downwardly at 3|! in the f direction of the passage 1, i. e., toward the furnace. This inclined wall 30 is discontinued at its lower end. Beneath it is a horizontal passage 23 parallel to the path of the ram 8 or nearly so and slightly greater in cross section than the feed block 20. This .latter fits and slides freely in said passage which is open at one end into the bottom of the hopper where it Joins the passage 1. The hopper bottom feed I! is caused to reciprocate across the bottom of the hopper in the direction of feed and at the point where the hopper Joins the passage I.

It is also of interest that the end of the block 29 which is disposed toward the furnace and in the direction of the feed is provided with an offset portion or step at 3| so that its lower portion protrudes at 32 beyond the upper por- 5 tlon II, the offset serving to break and aerate the fuel which is contacted thereby'preventing clogging and cramping of the feed passage 1 in the operation of the hopper bottom feed or auxilliary feed as herinafter described. 10

In the operation of the invention the hopper 6 being supplied with fuel and the furnace having been fired in accordance with the usual practice, the electric motor I being energized the fuel is fed from the hopper B horizontally 15 or at a slight downward incline through the passage 1 whence it falls into the ram passage 9 in, front of the ram 9 which is assumed to be withdrawn. When the ram 9 is advanced, the fuel is fed into the throat l9 and forwardly 20 into the retort thence it is forced upwardly into the combustion chamber where it moves gradually to both sides as it burns passing over the grate I to the dumpingbars or ash plates 5.

However, with the construction shown in 25 which the hopperi is spaced 'backwardly from the front of the furnace to allow sufilcient room for access to the me door 2, a uniform, dependable and sufficient supply of fuel can not be passed by gravity from the hopper 6 to the :0 ram passage 8, as. bridging and cloggin will occur resulting sooner or later in a complete cessation ofthe feed. In order to provide a uniform, dependable and regular feed of the fuel from the hopper 6 through the horizontal 35 or slightly inclined passage I to the ram passage 8, the hopper bottom feed or secondary ram II has been devised.

It will be noted that as the ram 9 is withdrawnopening the ram passage 9 to the ad- 40 mission of fuel, the secondary ram is is advanced breaking and advancing the fuel in the feed e I causing it to drop into the passage in front of the ram 9 which is in turn advanced pushing the accumulated charge of 65 fuel into the throat l9 of the retort I as the secondary ram I9 is withdrawn. When the member I8 is in withdrawn position the fuel which has been broken and disturbed in its advance drops into its path to be advanced in and by the next stroke of the member ll.

The secondary ram I2 is also-operated in correspondencevwith the ram 9, breaking and advancing the fuel which might otherwise'become clogged in the retort l.

When the hopper-bottom feed member ll is in its advanced position, its forward edge 33 and the shoulder II occupy a position above and slightly to the rear of 'the'forward end of the ram 9. Thus the feed member ll may be said to feed fuel by virtue of its forward movement directly onto the bottom of the trough or passage 8 ready to'be ejected by the ram 9.

By use of the improved mechanism, 1. e., the hopper bottom feed mm It in combination with the passage 1 and the ram 9, this bottom feed ram, preferably operating in alternation with the .rani I, all tendency to cramping andclogging 'backwardly away from the. fire door so as. to.

ive convenient access to the latter at all times for raking and breaking of the fire by hand. 7

acaaesc The particular type of bottom feed block it which is shown with the offset at the front serves an additional purpose in breaking and aerating the fuel, preventing clogging and cramping in the pa. age I, and also preventing .arching over the bottom feed ram or movable hopper bottom.

The improved device conveys Just the right amount of coal easily and quickly to the front of the ram. As already pointed out,- the dimculty incident to the location of the hopper immediately back of the fire door has been previously considered and attempts have been made to overcome it by spacing the ram and hopper back from the retort, but the increased length of the ram passage has caused clogging making the apparatus thus designed unpractlcal.

It is of particular importance that in the improved construction the ram is not required to advance thecoal any further than in constructions where the hopper is immediately adportant advantage in'favor of the new apparatus which has, in fact. overcome all diiiiculties incident to so placing the hopper that it does not interfere in any way with free access to the fire door for hand stoking and/or any other purpose.

We have thus describedspecifically and in detail an underfeed stoker embodyin the features of our invention in the preferred form in order that the manner of constructing, applying and using the invention may be fully understood. however the specific terms herein are used de- 5 scriptively rather than in a limited sense, the scope. of the invention being defined in the claim.

What we claim as new and desire to secure by Letters Patent is:

In a unitary fuel feeding mechanism to be placed outside of a furnace for feeding fuel to the furnace. a ram and a ram passage therefor. the ram being mounted to reciprocate in the passage. a fuel hopper having its bottom at a higher level than the ram passage and spaced l5 backwardly from the forward end of the ram in its rearmost position. a pusher mounted in the'bottom of the hopper and adapted to reciprocate in the direction of the ram passage. a\.' fuel passage connecting the bottom of the hopper to the ram passage. the fuel passage having its bottom surface inclined downwardly from the forward end of the pusher in advanced position to the ram passage at a point immediately in front of the ram in its rearmost position, means directly 2 connecting the pusherto the ram to advance the pusher as the ram is retracted and vice versa. and power means for reciprocating the ram and pusher whereby a portion of fuel is advanced by the pusher at each stroke from the hopper into the fuel passage beyond the top of the incline from which point it moves by gravity down the said inclinedsurface into the ram passage entering the same in front of the retracted ram to. be positively advanced by the ram on its next forward stroke.

JAMEB 1". TURNER. CHRISTIAN P. BREIDENBAUGH. 

